Demonstrators in Istanbul marched in anger over the conviction of a second man for the killing, five years ago of a prominent Turkish-Armenian journalist.
The family of Hrant Dink denounced the verdict, arguing the murder was a political assassination.
Nineteen other defendants, known to be Turkish nationalists were acquitted of being members of a terrorist organisation.
One protester said: “This case is a disaster.Those who committed this organised crime were dealt with as if it was just an ordinary murder.”
Yasin Hayal received a life sentence for conspiring to kill Dink. The actual killer, Ogun Samast, was given 22 years in July by a juvenile court.
Dink was known for promoting Armenian causes and his death has triggered EU concern over Turkey’s failure to protect freedom of expression.